What little is known of turtle locomotion suggests that there are tradeoffs between several factors affecting their locomotor mechanics and energetics. The overall goal of this research is to evaluate the mechanics and energetics of terrestrial locomotion in turtles for comparison with other vertebrates. Specifically, this research will (1) measure the cost of transport of turtles during terrestrial locomotion, (2) evaluate the locomotor efficiency of turtles in terms of metabolic energy consumption, and (3) determine the reliance of turtles on an inverted pendulum mechanism of energy recovery. The relative locomotor performance of turtles will be evaluated in three ways. First, measurement of the oxygen consumption of turtles during terrestrial locomotion over a range of speeds will determine their metabolic cost of transport. Second, comparison of the ratio of mechanical work to metabolic energy expended during level and uphill locomotion will quantify the locomotor efficiency of turtles. Third, the use of force platform analysis to measure the mechanical work recovery of turtles will address their ability to minimize mechanical work during locomotion. Together, these studies will determine if terrestrial locomotion costs turtles less metabolically than other vertebrates. The results of this research will help identify the factors that determine the metabolic cost of locomotion in all animals, including humans. Furthermore, this research will offer insight into a natural system involving slow muscles and potentially poor balance during locomotion, a situation analogous to locomotion in elderly humans.